Water leaks are often associated with plumbing fixtures such as hot water heaters, dishwashers, and bathroom fixtures. Many water leaks may go undetected for days, during which time great damage is done such as to carpets in homes. It is desirable to detect water leaking into a boat. Prior workers have used an expansion material in a confined space so that it expands, upon water contact, to push one electrical contact against another. Others, such as EHLIG, U.S. Pat. No. 3,200,388, disclose a material which dissolves upon contact with moisture, such as a salt tablet, and which permits electrical contacts to close. Others, such as HATFIELD, U.S. Pat. No. 4,020,478, have detected the presence of water by conductivity.
Likewise, sonic transducers have been developed. Currently on the market is such a transducer, SONALERT, a registered trademark of P. R. Mallory & Co., Inc. made under the POTTER U.S. Pat. No. 3,277,465, which discloses basic circuits for piezoelectric transducers. Also, the DUNDON ET AL., U.S. Pat. No. 3,331,970 discusses the necessity for matching the acoustic impedance with the transducer impedance. SWEANY ET AL., U.S. Pat. No. 3,890,612, has suggested that a horn of considerable size be placed upon the piezoelectric transducer to aid in its output.